What Do Kangaroos Eat And How Do They Digest It?

Kangaroos are herbivores, meaning they eat only plants. Their diet is mostly grass and shrubs, but what they eat changes with the seasons, the weather, and where they live. To digest this tough plant material, kangaroos use a unique digestive system that is different from cows and other grazing animals, relying on a large chambered stomach filled with fermentation bacteria rather than chewing cud.

What Do Kangaroos Eat In The Wild?

Kangaroos are grazers and browsers. Grazing means eating grass close to the ground. Browsing means picking leaves and shoots from bushes and trees.

The specific plants a kangaroo eats depend entirely on its habitat. Red kangaroos, which live in the dry outback, eat mostly grasses. Eastern grey kangaroos, found in wetter coastal areas, also prefer grass but will eat a wider variety of plants. Wallaroos, a close relative, are more likely to browse on shrubs and forbs.

A typical kangaroo diet includes:

• Native grasses
• Herbaceous plants and forbs
• Leaves from shrubs and low trees
• Occasionally fruits and seeds when available

Kangaroos do not eat meat. They are strict herbivores. There are no reliable reports of kangaroos hunting or eating animal protein in the wild.

How Do Kangaroos Select Their Food?

Kangaroos are selective eaters. They do not simply eat whatever grass is in front of them. They use their lips and front teeth to pick specific leaves and grass blades, often choosing younger, more nutritious plants over older, tougher ones.

This selectivity matters because older grass has more fiber and less protein. Younger growth is easier to digest and provides more energy. Kangaroos will also shift their diet based on what is available. In drought conditions, when green grass is scarce, they will eat dry grass and more woody shrubs to survive.

They are also known to eat certain plants that are toxic to other animals. Kangaroos have a higher tolerance for some plant toxins than domestic livestock, which gives them access to food sources that cattle and sheep cannot use.

How Does The Kangaroo Digestive System Work?

The kangaroo digestive system is the key to their survival on a low-quality diet. They are foregut fermenters, which means they break down plant material in a chamber at the front of their stomach before it reaches the main digestive tract.

This is similar to cows, sheep, and deer. But there is a major difference. Cows chew cud. They regurgitate food back into their mouths to chew it again. Kangaroos do not do this. They swallow their food and let their stomach do the work.

Instead of chewing cud, kangaroos re-chew their food during a process called “mastication.” They chew each mouthful of food very thoroughly before swallowing. This is a critical step because they cannot bring the food back up later.

Once swallowed, the food moves into a large, sac-like stomach. This stomach has a complex lining with folds that slow the passage of food. This gives bacteria and other microorganisms time to ferment the plant material.

What Role Do Bacteria Play In Kangaroo Digestion?

Like all grazing animals, kangaroos cannot digest cellulose, the tough structural fiber in plant cell walls. They rely on a community of bacteria and other microbes living in their stomach to do this for them.

These microbes break down cellulose through fermentation. The fermentation process produces volatile fatty acids, which the kangaroo absorbs and uses as its main energy source. The microbes also produce protein, which is digested further down the digestive tract.

This system is remarkably efficient. Research has shown that kangaroos produce very little methane compared to cattle. Methane is a greenhouse gas produced by microbes in the stomachs of ruminants like cows. The microbial community in kangaroos is different, producing less methane and more of a compound called acetate.

Scientists have studied this difference for years. Some research suggests that understanding the kangaroo microbiome could help reduce methane emissions from livestock, though no practical application has been developed yet.

How Does A Kangaroo Stomach Differ From A Cow’s Stomach?

This is one of the most interesting parts of kangaroo biology. Cows have a four-chambered stomach. Kangaroos have a single, large stomach that functions differently.

The kangaroo stomach is divided into two main regions. The first region, called the sacciform forestomach, is where fermentation happens. It is a large, thin-walled sac that holds food for a long time. The second region, called the tubiform forestomach, is a long tube that acts as a passageway. It also contains microbes and absorbs some nutrients.

Because kangaroos do not ruminate, they need their stomach to hold food for a long time. Food can remain in the kangaroo stomach for up to 30 hours. This extended retention time gives the microbes plenty of time to break down the tough plant fibers.

The lack of cud chewing means the kangaroo’s digestive system relies more heavily on chemical breakdown through fermentation than on physical breakdown through chewing. This is why their initial chewing is so thorough.

Do Kangaroos Chew Cud Like Cows?

No. Kangaroos do not chew cud. This is a common misconception.

Cows, sheep, and goats are ruminants. They swallow food, bring it back up to their mouths, chew it again, and swallow it again. This process is called rumination, and the material they re-chew is called cud.

Kangaroos are not ruminants. They are foregut fermenters, but they lack the ability to regurgitate food. They are sometimes called “pseudoruminants” because they ferment food in their foregut but do not ruminate. Their digestive strategy is different, but it is equally effective for their diet.

What Do Baby Kangaroos Eat?

Baby kangaroos, called joeys, drink milk from their mother. They do not eat grass or plants immediately.

A joey is born after a very short gestation period of about 30 to 36 days. It is tiny and underdeveloped. It crawls into its mother’s pouch and attaches to a teat. The milk the mother produces changes in composition as the joey grows, providing different nutrients at different stages of development.

When a joey is old enough, it begins to poke its head out of the pouch and nibble on grass. This is a gradual process. The joey will start tasting plants while still drinking milk. Eventually, it transitions to a fully plant-based diet.

Interestingly, the mother kangaroo can produce two different types of milk at the same time if she has a joey in the pouch and an older joey that is still suckling. Each teat produces milk tailored to the specific age of the joey using it.

Can Kangaroos Eat Human Food Or Crops?

Kangaroos can and do eat crops. Farmers in Australia sometimes report kangaroos feeding on wheat, oats, and other cereal crops. They will also eat garden plants, vegetables, and fruits if they have access to them.

However, this does not mean human food is good for them. Kangaroos are adapted to a diet of native Australian plants. Processed human food, bread, or large amounts of fruit can cause digestive problems. Their stomach microbes are specialized for their natural diet, and sudden changes can disrupt the fermentation process.

If you see a kangaroo in the wild, do not feed it. Human food is not part of their natural diet and can harm their health. Kangaroos that become accustomed to being fed may also lose their natural fear of humans, which can lead to dangerous encounters.

How Much Do Kangaroos Eat Each Day?

The amount a kangaroo eats depends on its size, age, and activity level. It also depends on the quality of the available food.

A large male red kangaroo can eat several kilograms of grass each day. Smaller females and juveniles eat less. When food is high quality and easy to digest, they need less of it. When food is dry and fibrous, they need to eat more to get the same amount of energy.

Kangaroos are also very efficient with water. They can go for long periods without drinking, especially the red kangaroo, which lives in arid regions. They get much of the water they need from the moisture in the plants they eat.